1. Field of the Invention
The invention relates to an arrangement for clipping small equipment modules, in particular electrical and electro-optical equipment modules, onto a support rail designed to carry a row of modules of this type. It therefore also relates to modules provided with such arrangements.
2. Description of the Related Art
A conventional form of mounting used for installation purposes, in particular for electrical installation purposes, implements support rails in the form of standardized shaped-section members organized to receive rows of small electrical and electro-optical equipment modules, in particular circuit and/or connection modules to which electrical wires and optionally optical fibers are connected.
Conventionally, the modules are mounted on the rails by being clipped onto them, as shown diagrammatically in FIG. 1 for a support rail 1'.
Such a rail 1 is fixed horizontally to at least one generally vertical carrying element, such as, for example, a vertical wall 2' of an equipment cabinet, or vertical members of a frame (not shown), the fixing being symbolized by a fastener comprising a bolt 3' and a nut 3".
Each module, such as the module 4', is provided with a clipping arrangement for clipping it onto the rail, the arrangement conventionally including a rigid hook-forming portion 5' organized to hook onto a top edge of a rail that is fixed horizontally, and to cause the weight of the module to be supported by the rail. A catch-forming portion 6' that is organized to move resiliently and mechanically relative to the remainder of the module, completes the mounting of the module by latching onto a bottom edge of the rail, and, depending on the position that it takes up, it either holds the module to the rail, or else it enables the module to be mounted on the rail or to be removed therefrom.
The portion 6' of a module is often provided with a shape, e.g. a blind hole, such as 7', into which the end 8 of a tool blade, conventionally a screwdriver blade, can be inserted so that the catch-forming portion 6' can be levered by means of the blade from a first position into a second position, and optionally vice versa when the portion 6' does not return resiliently to a given position.
The mouth of the tool-blade receiving blind hole 7' in a module is generally placed at the edge of the module, generally at the edge of or between other modules and as shown in particular in the sole figure of Document FR-A-2 708 385, and it is open towards the front of the module when the module is mounted on the rail so as to enable a tool blade to be inserted into it regardless of the objects or walls that might be placed in the vicinity of the module once the module is in place on the rail. In many cases, it is necessary to ensure a module can be accessed via at least one of its faces, a front face in this example, to enable action to be taken on it without having to dismount the module and any other module that is connected to it, and in particular without having to disconnect the wires and/or fibers that are connected thereto.
Unfortunately, there are many cases in which it can be impossible to access the mouth of the tool-blade receiving hole in a module after the wires or fibers for connection to the module have been connected thereto, as can be seen in FIG. 2.
If the module 4' shown in FIG. 1 includes a row of screw connection terminals 9' having their screw heads accessible on the front face, as shown in the front view of FIG. 2, and receiving wires 10' that are connected to the terminals so that said wires are substantially parallel to one another, as shown beneath the module, it can be difficult or even impossible to insert the tool blade through the layer of wires 10' into the blind hole 7' which, in this example, is assumed to be positioned centrally in the portion 6' in which it is provided.
If the terminals in the row of terminals are very close together, as is often necessary in the equipment modules under consideration, the spacing "d" between adjacent wires 10' can be too narrow to allow a tool blade to pass through.